This invention relates to a mining machine having nozzles distributed about on the periphery of a cutting drum in which the nozzles are controlled singularly or in groups by a valve for the discharge of liquid, preferably, high-pressure liquid from those nozzles directed toward the mine face. The mining machine of the present invention may take the form of a drum shearer loader, having a shearer or cutter drum or a heading machine or a drifting machine of the type used in underground mining.
It is known in the art to provide nozzles or groups of nozzles on the periphery of a shearer or cutter drum. The nozzles are supplied with highpressure water to boost the cutting action of the cutter picks and the nozzles can be supplied with lower-pressure liquid for controlling dust. Each of the nozzles or groups of nozzles is connected to a liquid supply line of the drum only when they are directed toward the mineral face. The nozzles on the part of the periphery of the drum which is remote from the mineral face are not supplied with liquid. The purpose for limiting the duration of discharge of liquid by the nozzles is to limit the consumption of liquid to an unavoidable minimum.
In this way, the consumption of power required to distribute and spray the liquid is reduced and the risk to the machine operative parts is obviated even when high-pressure liquid is used. However, an expensive control system is needed to ensure that only the nozzles or nozzle groups which are near the mineral face are energized to discharge liquid as the drum rotates.
During the operation of winning material from the mine face, the zone of nozzles on the drum which is to be supplied with liquid undergoes a change with respect to the position and size of the zone when the cutting horizon of the drum is adjusted. Changes to the spray zone for a cutting drum are particularly prevalent with a cutter or shearer drum of a heading or drifting machine. The machine is guided continuously in a vertical or horizontal direction over the heading or drift face during the pivotal movement of the support arm which carries the cutter drum. Changes to the spray zone are also prevalent in shearer-loaders, particularly when the direction of movement by the loader changes where the cutting horizons of the two cutting drums are adjusted. Every change in the direction of movement by the support arm for the cutting drum and any change in the cutting horizon brings the rotating cutting tools of a different zone of the drum into engagement with the mineral to be released from the mine face. Energization of the nozzles for the delivery of liquid therefrom precisely at the peripheral zone facing the material to be won must be precisely controlled not only because of the direction of pivotal movement by the support arm but also because the depth of penetration of the drum into the heading or drift face is frequently altered. Similar problems for controlling the discharge of liquid from nozzles occur with longwall mining machines, i.e., drum type shearer-loaders, since in the operation of such mining machines, the trailing drum is positioned to cut coal at the floor of the mine and the height of the cut by the trailing drum is determined by the diameter of the cutting drum at the leading end of the mining machine and by the inclination of the support arm for the drum at the leading end.